void ossimHistogramEqualization::initializeLuts()
{
if(theForwardLut.size() != 0 ||
theInverseLut.size() != 0)
{
deleteLuts();
}
if(!theAccumulationHistogram||!getHistogram())
{
return;
}
ossimRefPtr<ossimMultiBandHistogram> accumHisto = theAccumulationHistogram->getMultiBandHistogram(0);
ossimRefPtr<ossimMultiBandHistogram> histogram = getHistogram()->getMultiBandHistogram(0);
ossimKeywordlist kwl;
theAccumulationHistogram->saveState(kwl);
if(accumHisto.valid()&&histogram.valid())
{
long maxBands = accumHisto->getNumberOfBands();
for(long band = 0; band < maxBands; ++band)
{
// first we grab pointers to the histogram and the accumulation
// histogram
ossimRefPtr<ossimHistogram> h = accumHisto->getHistogram(band);
ossimRefPtr<ossimHistogram> h2 = histogram->getHistogram(band);
if(h.valid()&&h2.valid())
{
// lets get the number of indices.
ossim_uint32 numberOfIndices = (ossim_uint32)h2->GetRes();
vector<double> countForInverse(numberOfIndices);
theForwardLut.push_back(new double[numberOfIndices]);
theInverseLut.push_back(new double[numberOfIndices]);
// let's grab the counts array
const float* histoCounts = h->GetCounts();
// double maxIntensity = h2->GetMaxVal();
double maxIntensity = h2->GetRangeMax();
double maxCount = h->GetMaxCount();
// now pre compute the transforms
double *forwardLut = theForwardLut[band];
double *inverseLut = theInverseLut[band];
// double minIntensity = h2->GetMinVal();
double minIntensity = h2->GetRangeMin();
double delta = maxIntensity-minIntensity;
ossim_uint32 idx = 0;
// clear out the inverse
//
for(idx = 0; idx < numberOfIndices; ++ idx)
{
inverseLut[idx] = ossim::nan();
}
for(idx = 0; idx < numberOfIndices; ++ idx)
{
forwardLut[idx] = minIntensity + (histoCounts[idx]/maxCount)*delta;
ossim_int32 inverseIdx = h2->GetIndex(forwardLut[idx]);
if(inverseIdx >= 0)
{
inverseLut[inverseIdx] = minIntensity + delta*(idx/(ossim_float32)numberOfIndices);
}
}
// now solve the inverse lut
//
ossim_uint32 idxStart = 0;
ossim_uint32 idxEnd = 0;
while((ossim::isnan(inverseLut[idxEnd]))&&(idxEnd <numberOfIndices)){ ++idxEnd;}
if((idxStart!=idxEnd)&&(idxEnd<numberOfIndices))
{
std::fill(inverseLut,
inverseLut+idxEnd,
inverseLut[idxEnd]);
}
idxStart = numberOfIndices-1;
while((ossim::isnan(inverseLut[idxStart]))&&(idxStart > 0)){ --idxStart;}
if(idxStart !=0)
{
std::fill(inverseLut+idxStart,
inverseLut+numberOfIndices,
inverseLut[idxStart]);
}
idxStart = 0;
idxEnd = 0;
ossim_float32 valueStart = 0.0;
ossim_float32 valueEnd = 0.0;
while(idxStart < numberOfIndices)
{
idxEnd = idxStart;
if(ossim::isnan(inverseLut[idxStart]))
{
while(ossim::isnan(inverseLut[idxEnd])&&(idxEnd < (numberOfIndices-1))) ++idxEnd;
double length = (idxEnd-idxStart)+1;
valueEnd = inverseLut[idxEnd];
double deltaVal = (valueEnd-valueStart);
ossim_uint32 tempIdx = idxStart;
ossim_float32 count = 1.0;
double t = 0.0;
while(tempIdx < idxEnd)
{
t = (count/length);
t = t>1.0?1.0:t;
inverseLut[tempIdx] = valueStart + deltaVal*t;
++count;
++tempIdx;
}
idxStart = idxEnd;
valueStart = valueEnd;
}
else
{
valueStart = inverseLut[idxStart];
++idxStart;
}
}
}
}
}
}
ossimHistogramEqualization::~ossimHistogramEqualization()
{
deleteLuts();
}
rspfHistogramEqualization::~rspfHistogramEqualization()
{
deleteLuts();
}
